Abstract
A barley crop (Hordeum distichum L., ev. Zita) was grown in loamy sand in lysimeters, and exposed to drought either during the vegetative growth stage or during the grain growth stage. For the fully irrigated treatment in 1982 the growth rates of grains from main shoots and first tillers were 2.09 and 1.96 mg day-1 grain-1, respectively. Mainly because of a 2.4°C lower air temperature during the linear grain growth in 1985 the growth rates were lower, 1.63 and 1.28, respectively. For the fully irrigated treatments the daily increase in grain dry matter from all tillers were 27.6 and 22.7 g day-1 m-2 for 1982 and 1985, respectively, The lower temperature increased the duration of grain growth by 4 days. The growth rates of grains from normal shoots of the drought treatments (1.92 and 2.23 in 1982; 1.80 and 1.23 in 1985) did not differ significantly from those of the fully irrigated treatments (2.09 in 1982; 1.63 in 1985). Corresponding growth rates of grains from first tillers (1.90 and 2.28 in 1982; 1.26 in 1985) did not either differ significantly from those of the fully irrigated treatments (1.96 in 1982; 1.28 in 1985). In the humid temperate climate where this investigation was conducted, drought during the grain growth phase did not affect growth rates of grains until all plant available soil water had been utilized.